KARAKTERISASI MATERIAL REFRAKTORI BASA BERBAHAN DASAR MAGNESIA (MgO) DENGAN VARIASI SINTERING 1200oC, 1300oC, DAN 1400oC GUNA LINING TUNGKU INDUKSI PENGECORAN BAJA PT SUYUTI SIDO MAJU CEPER KLATEN

Abstract

Refractory is one type of ceramic that has ability to maintain its condition both physically and chemically and very stable at high temperature conditions. Refractory are used as insulation lining the furnace in metal smelting. However, most of the metal casting industry, particularly in Indonesia in the purchase of refractory materials based on a manual book submitted by the manufacturer of refractory without knows the properties and characteristics of refractory materials. This is caused by the lack of knowledge of refractory materials. This refractory material characterization study aims to determine the shape and grain size by meshing, the chemical composition refractory compounds with X-RD (X-Ray Diffraction), and the density and porosity of the refractory which are the physical properties of refractory. Refractory material in this research is consists of large and small aggregate that is used for induction furnace steel making PT Suyuti Sido Maju Ceper, Klaten. These materials are formed with a pressure of 240 MPa with mold dimensions are 17,8 mm diameter and 50 mm in height. The process of making the specimen through sintering process with variation of temperature at 12000C, 13000C, and 14000C and holding time 2 hours at maximum temperature. Heating rate for sintering this material is 100C/min and cooling rate of 200C/min. The results of refractory characterization is for a large aggregate refractory material has a grain size greater than 0,150 mm while the grain size for small aggregates are smaller than 0,150 mm. The grain shape for this refractory is rounded and well-rounded.. The chemical composition of the main constituent of refractory material is magnesia (MgO) with weight fraction ~ 95%. Density values for refractory magnesia (MgO) at a temperature of 12000C, 13000C and 14000C are 3,04 g/cm3, 3,08 g/cm3 and 3,11 g/cm3. And theoretically, the density values for magnesia (MgO) is 3,58 g/cm3. While the value of porosity for refractory magnesia (MgO) studied by 15,7%, 12,4% and 9,2% for the sintering temperature of 12000C, 13000C and 14000C. This shows that with increasing sintering temperature will affect the increase in density and lower porosity of the refractory material.